<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div>
        <input type="file" name="file" onchange="uploadFile(this);">
     </div>

     <div>
         <pre id="ret-content"></pre>
     </div>
     <script>
         function uploadFile(t){
             if(t.files.length <= 0)return;

             let fm = new FormData();
             fm.append('file',t.files[0]);

             fetch('/upload',{
                 method:'POST',
                 body:fm
             })

             .then(res =>{
                 if(res.ok){
                     return res.text();
                 }
                 throw new Error(`${res.status} ${res.statusText}`)
             })
             .then(text =>{
                 let d = document.getElementById('ret-content');
                 d.innerHTML = `<img src = "/image/${text}" style = "width:80%;height:auto">`;
             })
             .catch(
                 err=>{
                     console.error(err.message);
                 }
             )
         }
     </script>
</body>
</html>